P.Bowers Curtiss Aircraft 1907-1947 (Putnam)

Model F-5L

Although it clearly showed its ancestry in earlier Curtiss twin-engined flying-boats, the F-5L did not carry a Curtiss designation. Actually, it was not even a Curtiss design; it was one of several established European models chosen for production in the United States in 1917. The F-5L evolved from the original America of 1914 after Lt Porte, one of its designers, returned to England after the war began. For the Royal Naval Air Service he developed improved versions of the America, the several H-boats called Small Americas, and the H-12 Large America that Curtiss supplied to the RNAS. The first of the production British-built developments was the F.2, the F standing for the government aircraft plant at Felixstowe. The wings, empennage, and powerplant arrangement of the British F-boats were essentially Curtiss; Porte's principal contribution to the design was an improved hull. Porte's F.5 model was a parallel design to Curtiss's H-16. While the British F.5s used 345 hp Rolls-Royce Eagle engines, the American versions, redesigned to American standards by the US Navy, were built with Liberties, hence the letter L in the designation. The principal recognition points between the F-5L and the improved Liberty-engined H-16 was the horn-balanced parallel-chord aileron and balanced rudder of the former, and its noticeably different hull lines and open cockpits instead of the enclosed cabin of the H-16. Although the F-5L design belonged to the US Government, its well-known Curtiss ancestry, plus the fact that some were built by Curtiss, has caused it to be widely regarded as a Curtiss. Curtiss built sixty F-5Ls, Canadian Aeroplanes Ltd built thirty, and the US Naval Aircraft Factory built 138. After the war, redesigned vertical tail surfaces were introduced by the Navy on the two of the last three Navy-built F-5Ls which were redesignated F-6. These new tails were then retrofitted to all F-5Ls in service. When the Navy adopted an aircraft designation system in 1922, aircraft already in service retained their original designations but the F-5Ls unofficially became PN-5 (P for Patrol, N for Navy, regardless of actual manufacturer). Two F-5L hulls were fitted with entirely new wings and 525 hp geared Wright T-2 engines in 1923 and became PN-7s. Duplicate models with the hull built of metal instead of wood were PN-8s. Further Navy-designed variants continued up to PN-12, with production versions of the PN-12 being built by Martin as PM-1 and -2, Douglas as PO-1, Keystone as PK-1, and Hall as PH-1, -2, and -3 in the late 1920s and early 1930s. The Halls served into 1943 to carry the direct descendants of the America through two World Wars. Early in 1919 F-5L A3864 was modified by the Navy to a tandem-engine design to test the concept of one tractor and one pusher engine in a single nacelle for possible modification of the existing NC-1 and NC-2 three-engined flying-boats. This variant survived to March 1925. A number of surplus F-5Ls were converted to 16/20-passenger transports by several overwater airlines in the 1920-24 era. Postwar price direct from the Navy was $12,400 while new prices for Navy-built F-5Ls ranged from $56,099 less engines for the first to $20,495 for the last.

G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)

Curtiss F-5L

Production of the F-5L in 1918 put Curtiss in the odd position of building an improved foreign version of one of its own designs. A number of Curtiss H-12s and H-16s, developed from the original America flying-boat of 1914, had been sold to Britain in 1915-16. These designs had been improved upon by the Royal Naval Air Station at Felixstowe, and were put into large-scale production as F (for Felixstowe) -2, -3 and -5, powered with British engines. The wings and tail were essentially Curtiss, but the major improvement was in hull design, which permitted quicker take-off under heavy load and stood up better on the surface of the rough North Sea. Although Curtiss was producing later versions of the H-16, roughly equivalent to the British F-3, late in 1917, the Navy decided to adapt the F-5 to American manufacture and power it with the new Liberty engine. In addition to the Naval Aircraft Factory and Canadian Aeroplanes, Ltd, Curtiss was selected as a manufacturer and built 60. Canada built 30 and the NAF built 137, the last two of which were completed as improved versions, F-6L. The principal feature distinguishing the F-5L from the Liberty-powered H-16 was the use of ailerons with parallel leading and trailing edges instead of the distinctively tapered trailing edges of those on the earlier boats. Balance area was also added to the F-5L rudder, but this area was set into the fin beneath the horizontal tail and was not noticeable. After the war all the F-5Ls in service were fitted with much larger vertical tails of entirely new design, which the Navy had developed on the two F-6Ls. The F-5L was considered to be a US Navy design rather than a Curtiss, and when the new designating system of 1921 was adopted, the F-5L was assigned the designation PN-5 while the F-6L became PN-6. However, in practice the new designations were not used for designs in production before adoption of the new system, and the F-5Ls were called such until their retirement in 1928. Improved versions, in which newer wings and engines were fitted to the basic F-5L hull, did use the new designations, starting with the PN-7. The wooden-hulled F-5Ls, along with the near-duplicate H-16s, remained the standard patrol boats of the Navy until replaced by production versions of the NAF PN-12 built by Douglas, Martin an Keystone in the late 1920s.

O.Thetford Aircraft of the Royal Air Force since 1918 (Putnam)

FELIXSTOWE F. 2A

The most famous of the series of Felixstowe flying-boats used on North Sea patrols, some of which remained in service with the R.A.F. in 1918 and for a few years after the war. Fifty-three in service on 31 October 1918. Equipped Nos. 228, 230, 240, 247, 249, 259 and 267 Squadrons. Two 345-h.p. Rolls-Royce Eagle VIII engines and a loaded weight of 10,978 lb. Max. speed, 95 1/2 m.p.h. at 2,000 ft. Endurance, 6 hours. Service ceiling, 9,600 ft. Span, 95 ft. 7 1/2 in. Length, 46 ft. 3 in.

FELIXSTOWE F. 3

The F. 3 formed a link between the F. 2A and F. 2C flying-boats of the First World War and the post-war F. 5. It had greater wing-span than the earlier boats and a total of 96 F. 3s was on charge in October 1918. Equipped Nos. 231, 232, 247, 249, 259, 261, 263, 266 and 267 Squadrons. Two 345-h.p. Rolls-Royce Eagle V III engines and a loaded weight of 12,335 lb. Max. speed, 93 m.p.h. at 2,000 ft. Endurance, 6 hours. Service ceiling, 8,000 ft. Span, 102 ft. Length, 49 ft. 2 in.Felixstowe F.5

FELIXSTOWE F. 5

The F. 5 was the standard flying-boat in service with the R.A.F. in the years immediately following the Armistice in 1918. It was the last of the line of Felixstowe boats designed by Lt./Cdr. John Porte which served with such distinction in the First World War, but was itself too late to see active service. The F. 5's design followed fairly closely that of its predecessors, the F. 2A, F. 2C and F. 3. The prototype (N 90) went through its acceptance tests in May 1918 and proved to be over 10 m.p.h. faster than the F. 3, from which it differed in having a new wing structure of greater span (103 ft. 8 in., as against 102 ft. on the F. 3 and 9s ft. 7 1/2 in. on the F. 2A), a new type of wing section and numerous detail improvements. To facilitate manufacture, however, the production version of the F. 5 was extensively modified to incorporate F. 3 components, with the result that its loaded weight was increased and the final performance figures were somewhat inferior to those of the F. 3. The prototype F. 5 was built at the Seaplane Experimental Station at Felixstowe, but production aircraft were contracted out to Short Bros, at Rochester, the Gosport Aircraft Co. at Gosport, S. K. Saunders in the Isle of Wight, Boulton and Paul at Norwich (hulls only) and the Aircraft Manufacturing Co. at Hendon. F. 5 flying-boats equipped No. 230 Squadron at Felixstowe, moving to Calshot in 1922. Their task was naval co-operation with the Portsmouth submarine flotilla at Portland and exercises with the Atlantic Fleet. No. 230 Squadron was re-numbered No. 480 Flight at the end of 1922, but it retained its F. 5 boats until wooden-hulled Southampton were introduced in 1925. In July 1919 an F. 5 flying-boat (N 4044) made a tour of Scandinavia, a flight of 2,450 miles in 27 days. In December 1924 Short Bros, produced an F. 5 (N 177) with an all-metal hull, this being the first military flying-boat in the world to depart from the orthodox wooden construction.

O.Thetford British Naval Aircraft since 1912 (Putnam)

Felixstowe F.2A

Though it saw action only during the last year of the First World War, the F.2A earned a reputation comparable with that of the Sunderland in the Second World War. By virtue of its great endurance and heavy defensive armament, it bore the brunt of the long-range anti-submarine and anti-Zeppelin patrols over the North Sea in 1918 and figured in innumerable fights with German seaplanes; the exploits of Great Yarmouth's boats were typical, and are related at length in C F Snowden Gamble's classic, The Story of a North Sea Air Station. It established the trend of British flying-boat design for two decades and was a triumphant justification of the pioneer work of John Porte, who had from 1914 devoted himself unceasingly to the development of the flying-boat as a weapon of war. The F.2A was the first of the Felixstowe boats to be widely used by the RNAS. The first of the series was the F.1 (No.3580), which combined the Porte I type of hull with the wings and tail assembly of a Curtiss H.4. This was an experimental design only and was not put into quantity production. The success of the Porte I hull was such that it was decided to build a larger one on the same principles which could be married to the wings and tail assembly of the Curtiss H.12 Large America. The outcome of this idea was the Felixstowe F.2, the immediate forerunner of the F.2A. The Porte-type hulls offered greater seaworthiness than had been the case with the Curtiss hulls, yet their method of construction was such that they could be produced by firms with no previous boat-building experience. This was an obvious asset at a period of the war when the need for greater numbers of flying-boats for anti-submarine patrol was becoming urgent. The first F.2A flying-boats were delivered late in 1917, and by March 1918 some 160 had been ordered; by the Armistice just under 100 had been completed, and in the immediate post-war period some aircraft ordered under these contracts were converted on the production line to F.5 flying-boats. The total production of 180 would undoubtedly have been greater if a decision had not been taken by the Admiralty to issue extensive contracts for the F.3, a flying-boat in some respects inferior to the F.2A. As the F.2A had originally been intended for operation from sheltered harbours, it was necessary to make some structural modifications to the hull when its use became more widespread and indiscriminate. Nevertheless, the F.2A stood up well to harsh operational conditions, and such setbacks as it had were due not to lack of seaworthiness, but rather to the inadequacies of the fuel system, for the windmill-driven piston pumps failed all too frequently. One of the great advantages of the F.2A in view of its considerable range (some boats stayed airborne for as long as 9 1/4 hours by carrying extra petrol in cans) was the provision of dual control; this had not been available on earlier types, such as the H.12. Modifications to the boats to suit the ideas of individual air stations were quite common; one of the most noteworthy was the removal of the cabin for the pilot and second pilot, leaving an open cockpit. This improved both visibility and performance, and from about September 1918 was incorporated in aircraft as they left the works. F.2As of the Felixstowe air station inherited from the Curtiss H.12s the historic 'Spider's Web' patrol system. This patrol began in April 1917, and was centred on the North Hinder Light Vessel, which was used as a navigation mark. Flying-boats operated within an imaginary octagonal figure, 60 sea-miles across, and followed a pre-arranged pattern which enabled about 4,000 square miles of sea to be searched systematically. One flying-boat could search a quarter of the whole web in about three hours, and stood a good chance of sighting a U-boat on the surface, as submarines had to economise on battery power. Moreover, flying-boats had the advantage over other heavier-than-air anti-submarine aircraft in that they could carry bombs of 230 lb, which could seriously damage a submarine, even if a direct hit were not secured. The F.2A, despite its five-and-a-half tons, could be thrown about the sky in a 'dog-fight' with enemy seaplanes, and on 4 June 1918 there occurred one of the greatest air battles of the war, waged near the enemy coastline, over three hours' flying time from the RNAS bases at Great Yarmouth and Felixstowe. The formation of flying-boats, led by Capt R Leckie, consisted of four F.2As (N4295 and N4298 from Great Yarmouth and N4302 and N4533 from Felixstowe) and a Curtiss H.12. One F.2A (N4533) was forced down before the engagement, due to the old trouble of a blocked fuel line, but the remaining F.2As fought with a force of 14 enemy seaplanes and shot six of them down. During the action another F.2A (N4302) was forced down with a broken fuel pipe, but a repair was effected, and finally three F.2As returned triumphantly to base having suffered only one casualty. Following this action, in which the danger of being forced down on the sea with fuel-pipe trouble became only too evident, it was decided to paint the hulls of the F.2As in distinctive colours for ready recognition. Great Yarmouth boats were painted to the crews' own liking, and some bizarre schemes resulted; Felixstowe, on the other hand, imposed a standardised scheme of coloured squares and stripes. The scheme of each individual F.2A was charted, and copies were held by all air and naval units operating off the East Coast. The F.2a was also successful against Zeppelins. The most remarkable of these engagements was on 10 May 1918, when N4291 from Killingholme, flown by Capts T C Pattinson and A H Munday, attacked the Zeppelin L62 at 8,000 ft over the Heligoland minefields and shot it down in flames. Some F.2As, operating as far afield as Heligoland, were towed to the scene of action on lighters behind destroyers. This technique was first employed on 10 March 1918, and was originally part of a scheme to extend the flying-boats' range so as to mount a bombing offensive on enemy naval bases. One variation of the F.2A was built with the designation F.2C ( 65); it had a modified hull of lighter construction and alterations to the front gun position. Although only one F.2C was produced, it saw active service with the RNAS at Felixstowe. The F.2C, flown by Wg Cdr J C Porte, the famous flying-boat pioneer, shared the credit with two other flying-boats in the same formation for the destruction of a U-boat.

It is generally conceded that the F.3, though the subject of large-scale production contracts (263 ordered and 176 delivered), was in many respects the inferior of the F.2A. Admittedly it could carry twice as many bombs, but it was slower and less manoeuvrable, and hence lacked the qualities which had enabled the F.2A to take on German seaplane fighters in air combat. On the other hand, it was capable of a greater range. It first entered service in February 1918 and was not declared obsolete until September 1921. The prototype F.3 (N64) differed from production aircraft in having twin 320 hp Sunbeam Cossack engines instead of Rolls-Royce Eagles. It is recorded that it served operationally during 1917-18 with the Royal Naval air station at Felixstowe. It made its maiden flight in February 1917 and was finally written off in May 1918. The F.3 operated extensively in the Mediterranean, and in October 1918 accompanied the Naval attack on Durazzo in Albania. The operational requirements for anti-submarine flying-boats in the Mediterranean area were, in fact, so pressing that manufacture of F.3 flying-boats was undertaken locally in Malta dockyards. Twenty-three were built in Malta between November 1917 and the Armistice.

H.King Armament of British Aircraft (Putnam)

F.2A. Extraordinary technical and military qualities were possessed by this most famous of the 'Felixstowe boats' and only in comparatively recent years have these qualities received full recognition. Dating from 1917, the F.2A had an armament of Lewis guns concentrated in the forward part of the hull and at the waist. Typically, there was a Scarff ring-mounting in the bow for one or twin-yoked guns. This was sometimes, perhaps generally, of the familiar No.2 pattern, though there is some evidence to suggest that in a few instances a type of Scarff ring-mounting wherein the quadrant moved with the gun-carrying 'bow', and was invisible when the bow was at its lowest position, may have been fitted. This type of mounting, which will be mentioned again in connection with the Handley Page O/400 and which will be shown in official drawings in Volume 2, was one of several mountings designed by F. W. Scarff. Sometimes the F.2A had a pillar-mounted Lewis gun on top of the pilot's cockpit canopy; there was a single Lewis gun at each waist hatch behind the wings; and atop the hull in this same area was another gun, or sometimes twin-yoked guns. In some instances at least the waist guns appear to have had the Scarff compensating sight. The pillar carrying each gun was mounted at the outer ends of two superimposed struts, braced to an inboard member and allowing the assembly to be swung outboard. There was under-wing provision for two 230-lb bombs just outboard of the attachments of the wing hull bracing struts, the carrier being staved to the wing inboard. One experimental F.2A had two 'howdah' or 'fighting-top' gun-nacelles, each with twin-yoked Lewis guns on a Scarff ring-mounting at its forward end, built on to the upper wing. These guns further broadened an already commanding field of fire; for, compared with the H.12 tvpe of boat, the F.2 was well endowed in this regard, having a 'cocked-up' rear hull which permitted the midships beam guns to be swung outboard on their pillars so that their lines of fire could meet little more than twenty feet astern. For comparison with the Sunderland, and with flying-boats between, this contemporary description of accommodation and battle stations is offered: 'A gunner is located immediately below the fore gun-ring, and a table for his use extends from his seat to the nose of the hull. Underneath the table is an ammunition box and trays... Abaft is the station for the pilot and assistant pilot... Their seats are well upholstered with kapok cushions, which act as lifebuoys if required. The assistant-pilot's seat is made to hinge, so that a clear passage may be obtained for walking fore and aft. A few feet behind the pilot is the wireless cabinet, with operator's seat, while at the port side of this a ration box is fitted. The engineer's accommodation is situated aft, with a ladder giving access to the top deck. Further aft is the second gun ring, with an adjustable platform to allow a gunner to have a good range of heights...' In a photograph showing an F.2A built by the Aircraft Manufacturing Co. the sights on the beam gun are mounted on an arm on the gun's left side, with an eye-piece for the rear component. The forward gun, on its Scarff No.2 ring-mounting, does not have Norman vane-type sights, but apparently a form of ring-and-bead sight mounted laterally on the gun's axis.

F.2C. One experimental installation on this F.2A development was a compressed-air bomb-release system, eliminating the usual Bowden cable, but introducing its own problems of complexity and reliability. Only one F.2C was built. Flown by Wg Cdr J. C. Porte, to whom the greatest honour is due for developing the F-boats, this shared with two other machines of the same formation in the destruction of a submarine.

F.3 and F.5. Emphasis was placed, in the arming of these two flying-boats (1917 and 1918 respectively), upon anti-submarine operations, and the bomb load was accordingly increased to four 230-lb bombs. Machine-gun deployment was much as on the F.2 boats, the standard arrangement, as shown in an official publication on the F.5, being single Lewis guns at bow, dorsal and beam positions. No installation of a Davis gun or other heavy ordnance is known to have been made on a British F.3 or F.5, although interest in such armament was very much alive at this period and the American-built F.5 had an installation of the Davis gun. One Lion-engined F.5 for Japan is said to have had a revised bow cockpit for a '1-pounder shell-firing gun'.

F.5 (Metal Hull). Late in 1924 the upperworks of a Felixstowe F.5 flying-boat were fitted to an experimental metal hull of Short construction. Notwithstanding its experimental nature, this hull had two Scarff ring-mountings for Lewis guns. One was in the bow and the second in line with the trailing edges of the wings.

R.Mikesh, A.Shorzoe Japanese Aircraft, 1910-1941 (Putnam)

Hirosho (Hiro Naval Arsenal) (Hiro Kaigun Kosho)

The Hiro Arsenal was established on 1 August, 1920, under the name of the Aircraft Department, Hiro Branch Arsenal, Kure Naval Arsenal, as the Navy's first real aircraft repair and manufacturing factory. At that time, two Naval aircraft factories were operating at Yokosuka and Sasebo, but space was very limited. To increase production capability for the Navy, the Kure NavaI Arsenal expanded by establishing the Hiro Branch Arsenal three miles southeast of Kure on flat ground between the mouths of two rivers, the Hiro Ohkawa on the west and the Misakaiji-gawa on the cast. This new factory, known by its acronym Hirosho, was completed in October 1921, and licence-production of the F.5 Flying-boats was begun. On 1 April, 1923, the Hiro Branch Arsenal was upgraded to the Hiro Naval Arsenal to which the Aircraft Department belonged.

Navy F.5 Flying-boat

As a result of the British Aviation Mission that helped train the japanese Naval air force during 1921 and 1922, approximately ten types of British aircraft were taken to Japan by sea for instruction purposes. Among these was the Felixstowe F.5 built by Short Brothers, the aeroplane reputed to be the best of the large flying-boats. At that time, the Navy intended to build these aircraft for its own use, and had invited to Japan twenty-one engineers from Short Brothers for that purpose. This group, led by Shorts' engineer Dodds who arrived in Japan in April 1921, began work at the Ordnance Department of the Yokosuka Arsenal where the flyingboats were to be built. The japanese contingent under British leadership were Capt (Ordnance) Ryuzo Tanaka, Capt (Ordnance) Tomasu Koyama, Lieut Kishichi Umakoshi, Lieut Misao Wada, Engineer Masasuke Hashimoto and others. The manufacture of the F.5 was the start of many years of large flying-boat construction in Japan. In addition to the licensed manufacturing rights, Short Brothers supplied partially built assemblies to complete the first six of the F.5, in addition to assembly tooling and instruction in the manufacturing process. These F.5s were assembled at Yokosuka Arsenal, with the first one completed in April 1921. Since the F.5 was already renowned throughout the world as an excellent twin-engined all-wood flying-boat, it was no surprise that those assembled in Japan had excellent performance. When the first of them visited Tokyo, with a fly past in October 1921, there was impressed public reaction to their, then, enormous size. Following these imported and japanese-assembled aircraft, the flying-boat was put into full production at the Aircraft Department of the Hiro Naval Arsenal in the Kure area, beginning in October 1921. An additional forty F.5s were built by Aichi up until 1929. The engines initially used in these aeroplanes were the imported Rolls-Royce Eagle, which developed 360hp. As work developed, the Engine Factory of the Hiro Arsenal manufactured their first licence-built 400hp Lorraine engines in August 1924. In 1925, the Hiro Arsenal experimentally installed these new engines in one of the flying-boats and designated it the F.1. As the power rating of the Lorraine was increased to 450hp, another flying-boat was equipped with them, to become the F.2. Although the Hiro Arsenal expected that both the F.1 and F.2 would be adopted as standard equipment, the prototype aircraft were never put into production because the design of the airframe was already considered obsolete as it was based on First World War construction concepts. In addition to the prototypes, there were modifications of others, primarily in engine configurations, one version being powered by two 360hp Eagle direct-drive engines with faired nacelles, two-bladed propellers and Lamblin-type radiators. Only the F.5 version was taken into Japanese Naval air service. They were used as long-range patrol aircraft from 1922 to 1930, from bases at Yokosuka and Sasebo. They gave impressive service during their operational life, and numerous newspaper accounts covered their long-range over-water flights; but also during this time there were numerous accidents with deaths and injuries, the result of engine problems, improper maintenance, and bad weather. Nevertheless, the F.5 made its mark in Japanese aviation history.

Jane's All The World Aircraft 1919

THE FELIXSTOWE "F3" FLYING BOAT

The F3 Flying Boat designs emanate from the Seaplane Experimental Station, Felixstowe, but it has been built in quantity by Messrs. Short Bros. The boat is of the now well known Felixstowe construction with a wide Vee bottomed planing surface, fitted with two steps. The crew consists of a gunner in the nose, two pilots enclosed in a cabin in advance of the main planes, and a gunners cockpit in the rear of the planes with swivel mountings for Lewis guns firing out of the top and either side of the boat. The top plane has a considerable overhang and is fitted with ailerons of large area. Over the last set of struts are king-posts for bracing the overhang, the intervening space between the front and rear king-posts being covered in to form a fin.

Журнал Flight

Flight, July 31, 1919.

U.S.A. NAVY F-5-L FLYING BOAT

THE F-5-L boat seaplane is a twin-motored tractor biplane, having a total flying weight of nearly 7 tons, a cruising radius of 10 1/2 hours as a fighter, or 8 1/2 hours as a bomber. It carries a military load of over 1,400 lb., with a crew of four men. This machine is a formidable engine in naval war craft, and it is so designed that it may be quickly and efficiently made under war conditions. In the case of this machine the United States Navy, as did the Army, took a foreign design and modified it to meet American production methods. It is interesting to note, however, that in this particular case the English design had been based upon an American model, the large Curtiss flying-boat - the H 12 - which was the forerunner of both the H-16 and the F-5-L. The F-5-L is a somewhat larger machine than either the H-12 or the H-16, and is capable of carrying a greater useful load. It was originally developed at Felixstowe, and the name "F-5" was chosen to denote the English experimental seaplane factory at Felixstowe ("F"), and the model number design in machine ("5"). The United States Navy added the letter "L," indicating that, as built in U.S.A., it is driven by Liberty engines. The lines, overall dimensions and main constructional features were worked out in England, and an experimental plane was constructed there. The details with many modifications were worked out at the Naval Aircraft Factory, Philadelphia, to correspond to its production methods. The planes were then put into production at that and other factories, such changes from the first drawings being made as they were found necessary by tests. Fundamentally the plane is similar to the American Curtiss flying-boats - particularly the H-16 model. But in size and details it is quite different, being larger and better fitted to emergency production. For example, with few exceptions, the fittings are soft sheet steel, cut from flat patterns and bent to shape. This obviated the necessity of dies and drop forgings, which are particularly difficult to obtain under war conditions. The struts, likewise, are uniform sections, that is, not tapered, so that they can be shaped with a minimum of hand labour. Throughout, the parts are such that duplication is easy, production methods possible, and readily available equipment suitable. The most noticeable feature in the F-5-L is the degree to which the hull or boat has been streamlined. The hull cover sweeps aft, broken only by the cockpit openings. From an aerodynamic standpoint this is more efficient than the construction of the H-16, where a raised cabin is used. On this model, as on the H-16, the fin edges are continued aft, and join into the lower longeron, giving a much stronger and better streamline form. Another feature in the hull construction that is noteworthy is the use of veneer instead of linen doped and painted on the after hull sides. It was found in practice that the linen failed in heavy seas or on a bad landing, but this failure was obviated by the use of veneer. The specifications herewith will give some idea of the size and capacity of this seaplane. It will be noted that the lift, per square foot of surface is from 9.3 to 9.5 lb. per sq. and is somewhat greater than land practice.

With few exceptions, all large seaplanes have been previously built with unbalanced control surfaces. However, on the F-5-L both the ailerons and rudder are balanced. The purpose is, of course, to increase the controllability of the unit, and in the case of the aileron control the result is as anticipated. Differing from the usual control surface balance construction, the balance on these ailerons is cambered so that it has a positive lift. By this construction the ailerons tend to be more sensitive in their action and to operate with less difficulty and with less balance surface. The planing action is increased by the use of vents extending through the hull aft of the rear steps. Although the cabin top over the pilot's cockpit is eliminated, a certain amount of protection is afforded the pilot by small adjustable windshields. The whole lay-out of the machine is such that the duties of the crew may be most readily carried out. The observer's cockpit is in the nose of the machine, and from it the widest range of vision is possible. At the bow is mounted the bomb sight, and adjacent to it are the bomb-release pulls, ammunition racks, signal pistols, binoculars, etc. A machine-gun turret is mounted on the scarf-ring of the forward cock-pit. The pilot's cockpit is just aft the observer's cockpit, and may be readily reached from it when the machine is in operation. The pilots are seated on comfortable seats, hinged on a bulkhead and attached to a transverse tube by means of a snap-catch that may be instantly released. This permits the observer to pass aft at will without disturbing the pilot. A wheel control of the dual type is used. It comprises a laminated ash yoke on which are mounted the two aileron wheels connected by an endless chain. An instrument-board, containing tachometers, altimeters, air-speed indicator, oil-pressure indicators, inclinometer, and pilot-directing bomb sight is mounted directly in front of the pilot. On the starboard side of the hull are the individual engine switches, ammeters and emergency switches, together with the circuit breakers. The two compasses are mounted at some distance apart, so that they cannot interfere with each other. One is on the deck and the other on the floor. All instruments are self-luminous, but instrument-board lights are provided. The spark controls are at the starboard side of the starboard pilot's seat, but the throttle controls are between the two pilots, so that either may operate them. Fire extinguishers are placed conveniently at each station, those in the pilot's cockpit being attached to the bulkhead beneath the seat. The wireless operator's station is on the starboard side, just aft the pilots. The equipment is mounted on a small veneer table, and used in conjunction with a telescopic mast that is carried in the stern. A celluloid window in the hull side provides necessary light. The mechanics' station is amidships by the petrol tanks and pumps, and their main duty is to see that the plane is "trimmed" by pumping petrol from the tanks alternately; to see that the engines do not overheat, and that all parts function properly. The water and oil thermometer are mounted on the sidewalk beam adjacent to the mechanics' station. Aft the mechanics' station, or wing section, is the rear gunner's cockpit. Three guns are accessible from this station, and it also provides a good point of observation or position for aerial photography. All machines are equipped with inter-communicating telephones, the receivers being incorporated in the helmets and connection effected by terminal boxes at each station. It is thus possible for all members of the crew to be in constant communication. In addition to the equipment indicated, the following are some of the miscellaneous items usually carried: tool kits, water buckets, range and running lights, pigeons, emergency rations, drinking water, medicine chest, sea anchor, chart board, mud anchor, anchor rope, heaving lines, signal lamp, binoculars, Very's pistol, ammunition, life jackets, and possibly electric warmers. Included also are the priming cans, drinking cups and usually several personal items. All this is exclusive of the ordnance equipment of bombs, machine guns, etc. Considering the size of the machine and the amount of material carried, the performance is quite remarkable. In fact, it compares very favourably with the performance of land planes having the same specifications and not hampered by the heavy boat construction. The time required to get the machine from the water varies with the wind velocity, but with a 15-mile wind and the plane fully loaded, from 30 to 40 sec. is required. The speed at take-off is about 47 knots on the air-speed indicator, and a machine of this design has made a climb of 4,200 ft. in 10 mins. A horizontal speed of from 85 to 90 m-p.h. is attained, but on patrol duty they are generally flown at a more economical speed, such as 70 m.p.h. When geared Libertys were tried out in one of these machines a speed of 102 m.p.h. was attained, but this was a special power-plant equipment. The engine revolutions are about 1,500, though this, of course, varies with the types of propeller used. At full speed the petrol consumption is about 65 galls, per hour, and the oil consumption about 2.6 galls, per hour. By throttling down the engine to 1,350 r.p.m., or to a speed of about 60 knots, the petrol consumption per hour is reduced to 44 galls., the oil consumption remaining the same. This gives a maximum cruising time of 10.6 hours with a light machine, or 8 1/2 hours fully loaded. The cruising time at full speed is 7.3 hours and 5.9 hours respectively. The advantages of operating at cruising speed are many, and it is at this speed that the plane is chiefly operated. Among the advantages are increased engine life, greater ease of control, longer cruising radius, less strain on plane parts, and time for more extended observation. When running at full speed, control is not particularly easy, though under normal conditions one pilot can operate the machine without difficulty. However, the reserve control is necessary to lift the machine from the water, and in cases of emergency, though not ordinarily used.(To be concluded.)

Flight, August 7, 1919.

U.S.A. NAVY F-5-L FLYING BOAT(Concluded from page 1026)

THE hull is built up around four longerons, as is a land plane, and has in addition a keel and a planked V-bottom that is flared out to present more landing surface. The flared out portions are called fins, and in this place are an integral part of the hull structure, and are continued aft, and streamline into the hull sides. This is not the case in many previous seaplanes, namely, the H-12 and the HS-1 and 2, where the fins are stopped abruptly about one-third the hull length aft from the bow, and the advantage is increased strength and better streamline form. Before entering into a detailed description of the hull construction, it may be well to define some of the terms used. The following defines them roughly, and is the order in which they enter the hull construction :- Keelson. - A wide thin plank extending from near the bow to the stern, above the keel. Keel. - The bottom-most longitudinal member forming the backbone of the hull. Floor Frames. - The transverse planks jointed at right angles to the keelson. Longerons. - All longitudinal members extending from the bow to the stern with the exception of the keel. Fin Edges. - The two outside longitudinals of the fins. Stringers. - The longitudinal strips connecting the floor frames on the bottom and the strips on the fins. Bulkheads. - All transverse veneer structures dividing the hull framing. Transverse Bracing. - The central structure connecting the hull to the two wing beams extending through the hull. The keelsons are 1/2-in. basswood, built in not more than five sections, having a t least a 9-in. scarf at the joints and held together with copper rivets. To this the floor frames, also 1/2-in. basswood, are notched and securely riveted by two corner stringers. Throughout it will be noted that built-up members are used, permitting the use of readily available material. White ash is used for keel, longerons, fin edges and the bent ends of the stringers. These two may be built up or spliced, but not more than four sections may be used. The scarfs in the keel must be at least 18 ins. long, and are copper riveted. Formerly a straight scarf was used, as it was considered a better production proposition, but now a stepped scarf is used, as it was found that the time saved in making the straight scarf was lost in assembly. Similar methods of splicing are used in the case of the longerons, fin edges and stringers, and here the joints are served and doped. Care is taken in the location of all splices in longitudinal members, so that a number of splices will not occur in any one section, causing a weak section and failure. For example, not more than two longeron splices may appear in any one bay, and these must both appear in either the upper pair - to balance each other. By this method of splicing ash longitudinals, and the careful location of joints, short lengths of ash can be used. And this is important, as airplane ash under any condition is not easy to secure. All ash members are steam bent to assembly shape before assembly on the hull forms. This bending and the splicing of the complete longitudinals are done in a separate part of the shops. Likewise the keelsons and floor frames, stringers, bulkheads, posts, struts, braces, etc., are sub-assembled, and when delivered to the hull erection floor are ready for assembly but with little fitting. This idea is carried out even to the bottom planking, which is delivered in amounts sufficient for one hull. But a detailed description of this sub-assembly is too involved for comment here. Throughout the hull construction all parts are tied together by metal fittings - and concerning these metal fittings three points are noteworthy as aiding increased production. The first is a choice of material used. One generally considers the steel entering into airplane construction as being the best possible, and heat-treated to the greatest strength. But fittings on this plane are in general soft or mild carbon steel. The reasons for this are that such steel can be procured almost anywhere, is easily worked and welded, and loses little of its strength through abuse in brazing, welding or forming. The second point to be noted in the fittings is that, with few exceptions, they are built up from flat patterns bent and brazed or welded. This eliminates drop forgings, which were so difficult to secure, and permitted production to go ahead without waiting on the construction of dies. The third feature of the fittings is the use of identical fittings in many places. For example, throughout the hull, the junction of the posts and the longerons, the point of attachment of the floor frames to the longerons, and the plates covering the joints of the hull bracing - fittings differed only slightly at the different stations. However, originally each similar fitting differed slightly, necessitating a separate template, a separate print, part number, operations, etc., throughout the whole construction. But a study was made, and an "average fitting" produced that would suffice for several similar stations. The fact that such fittings did not exactly fit anywhere, or had lugs that were not needed in other places, amounted to less than they saved time in production. And they were structurally as good. A further difference in the construction of this hull and that of similar hulls of its predecessors is to be noted. On previous models, riblets were used to connect the keel with the fin edge stringers. These riblets were about 1/2 in. by 1/2 in. ash, spaced at distances varying from 9 to 15 ins. transversely across the boat bottom. To bring their bottom surface flush with the stringers, lower longerons and fin edges, it was necessary to notch keel, stringers, longerons and fin edges that they might be set in. And it was a slow, tedious job. On this unit, the riblets are omitted, though several ash-tie strips are used to connect the keel with the fin edges. It is considered that these, together with the planking, provide transverse strength in abundance. Another feature in the construction is the extensive use of steel tubing as struts and posts in the body bracing. This is particularly noticeable in the tail, where the parts are under no great strain, and are not used for the attachment of other parts. Steel tubing is readily procured, and ready for use by simply cutting to length. The central or transversal bracing unit is a complete unit in itself, and is set up as a separate assembly previous to installation in the hull. This differs from the usual construction and permits the use of templates to assure accuracy. The transverse bracing connects the hull to the wings and the hull may be said to be built around this unit. By making all transverse bracings identical, any set of F-5-L wings, engine mountings, etc., may be more readily installed. It is also to be noted that the wing spars passing through the hull are spliced at the centre. These spars, styled the sidewalk spars, as they carry a short veneer covered wing section at each side of the hull that is used as a sidewalk for the mechanics to reach the engine, may be removed when the hull is packed for shipment, permitting the use of a much smaller shipping crate. The bottom planking comprises an inner and an outer skin, each of 7/32-in. cedar. The inner skin is placed at right angles to the keel, differing from usual practice wherein both layers are at an acute angle to the keel. As riblets are eliminated, the right-angled inner planking tends to replace them as strength members. This inner planking is either Port Oxford or Spanish cedar in random widths of from 4 to 10 ins. The outer planking is placed at an angle of 45 deg. to the keel, the acute angle being on the aft side. All pieces are from 4 to 5 ins. wide, Spanish cedar, and are screwed to all longitudinals. The two layers of planking are secured together by brass clinch nails. Courtrai, a special fabric, is laid in marine glue between the two layers of planking, and is used extensively in rendering all joints tight. All planking is laid with a slight clearance to allow a go-and-come resulting from moisture changes. The bottom steps are secured in place after the hull is planked. They are two layers of 7/32-in. mahogany planking, fabric and marine glue between, screwed and clinch-nailed together, and secured to the hull bottom by copper rivets, being separated from it by triangular ash strips. The forward ends of these steps are scarfed and set into the hull planking, a thick brass strip being set in flush over the joint. For the rest of the hull 1/8-in. three-ply waterproof veneer is used. The top plane is built up in five sections, comprising a centre section of 13 ft. 6 ins. span (108 sq. ft.), two intermediate, 27 ft. span (216 sq. ft. each), and two outer extensions, 15 ft. 11 ins. span (95 sq. ft. each). The lower plane is in four sections, consisting of two centre sections (or sidewalks) mounted one on each side of the hull, giving the same overall span as the top centre section and having a combined area of 66 sq. ft. The balance of the lower surface consists of port and starboard wings, 30 ft. 5 ins. span (240 sq. ft.) each. Vertical "non-skid" fins are mounted above the top planes at each outermost interplane strut. An extended technical description of the panel, strut and tail construction could be expanded to many volumes. But the outstanding features of these are laminated spars, simple strap type wing and strut fittings and laminated uniform section struts. At one time laminated or spliced spars were not in favour, but the shortage of long spruce necessitated the use of laminated and spliced spars, and it is found that the laminated spar is better than the unlaminated one. Outside of the economy of material, the ease of drying pieces of small cross section and the resulting dependability of built-up spars more than off-sets any additional expense in manufacturing. Two types of laminated spars are used - the two-piece and the three-piece. The former is simply two pieces placed back to back, and glued together. The two halves are of equal thickness, and are lightened as was the solid spar except at splice positions. Scarfed splices are used, and staggered in the two halves. The two-piece is used in the following places: all front spars (except engine section), horizontal stabiliser spars, and rear aileron spars. The three-piece spar comprises a thin piece sandwiched between two thicker outside pieces, glued together, and lightened similar to the solid spar, except at splices. This construction is used in the sidewalk and engine section, or for rear spars. Of the two types, the two-piece is considered stronger, and hence the above distinction of their use. The idea of using strap fittings and the elimination of forgings and machined fittings extends to the strut and wing fittings. Here also mild carbon steel is used, cut from flat patterns and bent to shape. The base wing fitting is a U-strap, bent around and bolted to the spar. From it lugs are bent for interwing wiring, and the interplane side has a cloverleaf extension for the attachment of the struts and wire terminals. These are reinforced by washer plates to provide bearing for the bolts. Roughly, the spars are secured to the strut ends by a bolt passing through the central clover leaf and the strut end, and the usual strut socket is eliminated. In detail, the strut end is squared down, drilled to mate with the central cloverleaf hole, and a steel tube fitted in the end to give greater bearing and prevent the strut end from being crushed when the through-bolt is tightened. The through-bolt has a standard eye head, permitting the attachment for the drift and anti-drift wires, where a single wire is used. When double drift wires are used, the through-bolts holding the flying and landing wire clevises are made with an eye. Bearing for the strut ends on the spar is secured by means of a thin bearing plate between the strut and the spar. It was observed that considerable time was lost in shaping the tapered streamline section struts, and furthermore, these being in two-piece construction, required thick material that was difficult to obtain. Hence, a three-piece uniform section strut was chosen. As stated, this strut is three-piece, and all the lightening is done in the central portion. In the rough it is a flat board, the length and width of the strut, with a series of oval holes cut out of the central portion on a vertical spindle shaper. The cheek pieces are then glued on each side, and the strut rough-machine planed to a streamline section. It is then finished to the desired section by hand. Two Liberty engines comprise the power plant. These engines are identical with the engines used by the Army, with the exception of the pistons, which pistons are given more clearance, so that the compression pressure is reduced. The result is a slight reduction in maximum horse-power, but greater engine life. This is advantageous because in seaplane service long patrols place a premium on dependability and a seaplane does not habitually frequent high altitudes or require the maximum available horse-power. In the main, the engine mounting differs only slightly from the mounting of the Liberty engines in the Curtiss H-12 and H-16 seaplanes. Horizontal laminated engine bearers are carried on wooden V-struts over each main wing hinge fitting, and are attached to the upper panel by tubular A-struts. The radiator is carried on a bracket at the front, and the oil supply in streamlined tanks at each side of the bearers. However, in details, the F-5-L mounting is simplified and made a better production-proposition. The first step was the elimination of drop forgings. Strap fittings built up and brazed together are used for attachment of bearers to V-braces, and the upper attachment of the A-brace to the engine section is also a strap fitting. This attachment is strong and simple. The ends of the tube are first fitted with a tubular sleeve, and then formed to a U-section. In addition to the simplicity of construction, this end is extremely rigid. The A-braces are attached to the spar fitting through a universal joint bearing plate. This is also a built-up fitting. The forward A-brace is bowed to clear the engine cylinders, and the halves are tied together by a cross-tube and through bolt. This brace must be removed before the engine can be taken from the plane, and the removable cross-tube and through bolt permit this to be done. Differing from previous construction, the engine bearers are carried forward so that a straight radiator bracket may be used. Previously, the bearers were cut off by the front engine flange and arched brackets used. However, the straight bracket is simpler to construct, and is possible, on Liberty installations. In an installation of this nature, it is, of course, impossible to start the engines by hand cranking on the propeller. For this reason a rear hand starter, comprising a reduction gear and clutch engaging the crankshaft is used. One man can readily turn the engine over, though two are generally used. As stated, the oil tanks are streamlined, cylindrical, and mounted at each side of the engine bearers. The total capacity per engine is 17 galls., and the two tanks are connected by a manifold, the division simply being constructional. In later planes the side oil tanks are being superseded by one streamlined tank mounted between the engine-bearers and behind the engines. Tins serves to clean the installation up to a marked extent. A long-distance thermometer bulb is installed in the oil return line, and the gauge is mounted in the mechanics' compartment by the tanks. The oil-pressure gauge is installed on the pilots' instrument-board. A water thermometer gauge likewise is in the mechanics' cockpit. This location of the thermometers is because engine temperatures are of enough importance to demand quite frequent attention. The petrol supply is carried in five tanks placed amidships in the hull. There are two large cylindrical vertical tanks, one fore and aft horizontal tank, and two transverse horizontal tanks. The latter two were originally consolidated, but the single tank could not be removed without taking the plane to pieces. All have a total capacity of approximately 498 galls. As these tanks are below carburetor level, a header or gravity tank is necessary. This is located in the upper wing, between the two engines, and carries about 20 galls. The petrol is pumped from the hull by a double-barrelled windmill pump, and forced into the gravity tank sump. From the sump leads are taken to the two engines, and the surplus over this amount flows through small holes in the sump sides into the gravity tank. When the gravity tank becomes full, an overflow pipe carries the excess back through a sight box into one of the tanks. This overflow serves to show the mechanic that petrol is being pumped, and that the gravity tank is full. The construction of the gravity sump is noteworthy. It will be noted that the base of the sump is somewhat below the bottom of the tank, and that the two are only connected through small holes at the sump sides. Hence if the gravity tank be shot away, the supply of petrol pumped may be shut down to the amount used, with the base of the sump alone serving as a header tank. A semi-rotary hand pump is used to fill the gravity tank when the windmill pumps are inoperative. This pump is an English design, and a similar pump is also used for bilge water. The leads from all the supply tanks are consolidated into one manifold, and by regulating the valves petrol may be pumped from any tank into the gravity tank. However, it all returns into the starboard forward vertical tank, and in flight petrol is pumped alternately from this tank and each of the other tanks in rotation. It is necessary to pump from the tanks in rotation in order to trim ship, and a separate manifold would be necessary to return the overflow petrol to any tank. It is to be noted that the manifold incorporates a filler-valve piped to a union at the hull sides. This serves for the attachment of a pipe-line from a supply boat or tank that the seaplane tanks may be filled by petrol under pressure. Though this method of filling is not much used, it is stated all the tanks may be filled thus in a few minutes, whereas the funnel and measure method takes from a half to one hour. There are few other points of interest in the petrol system, standard sumps being used to prevent water and dirt from reaching the engine and dial gauges being used on the tanks to show the gasoline supply at hand. Throughout the system all pipe-line connections are through olive joints, and the features here are ease of connection, flexibility, and the fact that full flow of petrol is permitted. As an aid to starting, a small hand primer permits raw petrol to be pumped into the intake manifold. The outstanding features of the flying controls are the laminated-yoke dual elevator and aileron control mounting, and the adjustable rudder bar installation. The yoke itself is built-up of 1/8-in, laminations of ash, glued and riveted together, making a strong and light construction. Each end is extended to form the elevator throw, and the aileron control wheels arc mounted on brackets at the top. These wheels are connected by an endless chain, from the middle of the lower part of which are taken the aileron control wires. The cross-tube is integral with the yoke, and the whole swings on bearings at the hull sides. In addition to lightness of construction, rigidity, and simplicity of wiring, this control affords a maximum amount of room for passing from the front to the rear cockpit, and does not interfere with the legs of the pilots as does a post-type control. Originally, adjustment of the distance between the pilot and the rudder-bars was effected by shifting the seat. But this also brought the control wheel closer, and the installation was complicated. Adjustment on this plane is effected by shifting the rudder-bar bodily fore and aft the required amount. The rudder-bar is carried between two straps that are supported on a tubular framework in front of the pilots. These straps have a series of holes, and the rudder-bar may be set to swing on a pin passed through any one of these. A similar adjustment permits the outer end of the bar to be set properly in connection with the rudder-cable. As these pins are set in place by a small brass cotter, any desired setting can be made quickly. Under severe flying conditions, or in the case of tail or nose heaviness, it is sometimes necessary for the pilot to exert a continuous pressure on the controls. On the elevator or rudder controls, this continuous pressure may be applied at will, in any desired amount through rubber cords, called "bungies." The complete bungy is simply two pieces of rubber cable, connected by a small chain, and having both ends secured to the hull sides. The chain passes adjacent to the control it governs, and is hooked to it at will with a snap-hook. The pressure is applied to the control by extending the rubber cable before the attachment of the chain. All control cables are carried on brass ball-bearing sheaves, and the sheave-housings are fitted with guards to prevent the cables from coming off. With the exception of the point where the aileron cables pass through the upper wing, all control cables are open to inspection.

Flight, August 21, 1919.

THE E.L.T.A. SHOW

THE AIRCRAFT EXHIBITION

The British Section

THE GOSPORT AIRCRAFT CO. At the time of writing, the exhibits on this firm's stand consist chiefly of large panels giving particulars of the various types of Gosport flying boats. As these particulars were published in our issue of July 31, 1919, there is no need to repeat them here. One of the Gosport flying boats arrived by air on August 8, and was anchored in the Ij, close to the exhibition, where it was in the company of a large British Royal Air Force flying boat, also, we believe, built by the Gosport firm, although technically belonging to the Air Force. During Saturday and Sunday the small Gosport boat made flights over the river and harbours, to the great enjoyment of the Amsterdammers, who look with interest on any craft connected with water transport, and especially so when such craft combines water and air transport. The little Gosport flying boat gets off very well on the smooth waters of the Ij, and this firm, as being the only one to have a flying boat in commission at present, should do very good business in Amsterdam. During last week this boat was brought up to the show and placed on the Gosport stand.

Патрульные самолеты Феликстоу окрашивались очень пестроThe Felixstowe flying boats gave valuable service around the shores ol the UK in a variety of roles. but primarily on anti-submarine patrols. This aircraft, N4545. arrived at Felixstowe in July 1918 and joined 230 Squadron, which, in August, farmed out of the Antisubmarine Patrol unit.An R.A.F. Flying-Boat of Lieut.-Col. Porte's design, and known as the Felixstowe F2a Type, built by various companies. Dazzle-painted, in accordance with Naval custom.

Anti-submarine patrols were as important in the Mediterranean as they were around the UK and a number of specialist Flights were formed to perform these duties. Four such Flights (Nos. 360 to 363) were based at Calafrana, Malta, and in August 1918 joined to form 267 Squadron. Felixstowe F2a N4488 served with this unit.

In this view of F.2A number 8677 a man is obstructing the waist hatch. Clearly, however, the mounting above the hatch is not of the Scarff No.2 type, and there is doubt, moreover, if the mounting in the bow is of this pattern. Even the Lewis guns appear non-standard. Beneath the wing is a flat-nosed 230-lb anti-submarine bomb.

The U.S. Naval Seaplane N.C. 4 arrives at Plymouth, completing the crossing of the Atlantic by the air. The N.C. 4 is to the left in Plymouth Harbour, and taxying is British Seaplane N 4499, flying the British and American flags, on its way to greet the voyagers.

A Felixstowe F.3, rebuilt at Hamble by Fairey in 1920, at Funchal on 22 March, 1921, after the first flight to Madeira from Lisbon. Captain and navigator, respectively, were Sacadura Cabral and Gago Coutinho, who were later to cross the South Atlantic in Fairey IIIDs.

If nothing else, the Felixstowe F 5 should have served to highlight some of the shortfalls in British production engineering practice compared with that of the Americans. The prototype of this large maritime patrol aircraft had first flown in April 1918. However, the first production F 5 did not emerge until a year later, differing in considerable detail from the prototype. Compare this with the progress on the Americanised version of the F 5, the Navy Aircraft Factory F-5-L that first flew in late July 1918 and yet 33 of which had been delivered by the time of the November 1918 Armistice. Powered by two 325hp Rolls-Royce Eagle VIIs, or 375hp Eagle VIIIs, the F 5's top level speed was 88mph at 2.000 feet. Seen here is serial no N 4637, the eighth of a 50 aircraft batch of F 5s built by Gosport Aviation Company.

The Short S.2 metal-hulled Felixstowe F.5 conversion of 1924, which was developed from that company's Silver Streak of 1920, the first British aeroplane to be constructed entirely of metal. Though slightly heavier than the F.5, this was more than made up for by the elimination of several hundred pounds of water seepage in service. The water performance of the S.2 was also dramatically proven when, off the coast of France, the aircraft was stalled into rough water from a height of 30ft (9m) and remained undamaged and completely watertight. Thereafter, all Short flying boats were built of metal, and other manufacturers followed suit after development of their own constructional methods.

Essentially an improved version of the Curtiss H-16, via the John Cyril Porte developed Felixstowe F 5, the first Navy Aircraft Factory F-5-L made its maiden flight in late July 1918. Powered by two 420hp Liberty 12As, the four man F-5-L carried six .303-inch Lewis guns for its defence, along with up to four 230lb bombs for more aggressive purposes. Top level speed of the F-5-L was 90mph at sea level, with a range of 830 miles being attainable at its economic cruise speed. Besides being responsible for the design's 'Americanisation' in terms of its production engineering, the Navy Aircraft Factory went on to produce 138 of these flying boats, of which 33 had been completed at the time of the Armistice, or just over three months after the F-5-L's first flight. Clearly considered a priority naval programme, 60 more F-5-Ls were built by Curtiss, while a further 30 were completed in Canada before post-war contract cancellations took effect.

Components of the automatic pilot made by the Phoenix Dynamo Co and believed fitted to Felixstowe F.3 N4409 (c/n 208) for trials. The main attitude-sensing devices were mercuryfilled circular tubes which acted as switches for electrically-operated compressed-air flying controls.

British Felixstowe F.2A twin-engined flying-boat 4305 from Great Yarmouth burning on the water off Lowestoft on 31 July 1918, yet another victim of the speedy Brandenburg W29 and the aggressiveness of Christiansen's IC Staffel. Once again Leutnant Ehrhardt secured photographs of the action, and his series of six pictures showed that the boat had been hit and set on fire in the air during the first attack by the five-strong W29 formation. Previous encounters with these boats by the slower Brandenburg W12 had not always been successful, but the extra speed of the new monoplane meant that closure to effective firing range was now assured.